Near-Field
Communication (NFC) is an emerging wireless technology that expects to
revolutionize a range of mobile applications. However, the widespread use of
NFC is hindered by the fact that only a limited number of platforms have
built-in NFC support. Moreover, while NFC's short communication range offers
some degree of physical protection, recent findings have revealed NFC's
vulnerability to malicious eavesdropping.

This
project develops alternative NFC technologies that are secure and compatible
with legacy mobile devices and existing infrastructure (e.g., POS terminals).
The key novelty of this approach is to leverage visible light and acoustic
channels to realize NFC systems with robust performance and security assurance.
Due to the high directionality of narrow light beams, visible light can enable
secure and interference-free wireless links. Similarly, acoustic signal can be
modulated for NFC communication in close proximity. This approach offers
several key advantages over the existing NFC technology. Both visual and
acoustic communication channels can be implemented using prevalent components
such as LCD displays, microphones, and speakers, which lead to purely
software-based solutions that can easily retrofit existing infrastructure with
NFC functionality. Second, in contrast to RF channels, the direction and
distance of screen-camera link are controllable, preserving the communication
privacy and security. Similarly, integrated with physical self-jamming techniques,
the acoustic link can achieve information-theoretic security without the need
for pre-shared secrets.

In
this project, a new form of Visible Light Communication (VLC) is employed to
implement NFC, where 2D barcodes are streamed between LCD display and camera. A
new barcode design and several techniques are used to optimize the throughput
of screen-camera link, which include code block adaptation and re-ordering to
mitigate the impact of image blur in mobile environments, and lightweight image
processing algorithms for real-time decoding of barcode stream. A systematic
security study is conducted on barcode-based communication based on geometric
analysis and a new acoustics-based NFC system is developed for smartphones
without the need of a priori knowledge of security secrets. The emerging
friendly jamming techniques are utilized for establishing an
information-theoretically secure communication channel for NFC. This project
also explores advanced coding techniques, high-level modulation schemes and
other physical layer techniques for further improving the data transmission
rates and ensuring confidentiality guarantee.

Synopsis

Near-Field
Communication (NFC) is an emerging wireless technology designed for low-power communication
between devices within close proximity (e.g., a few centimeters). The close
communication range, as a result of fast decaying magnetic induction between
the antennas of NFC transmitter and receiver, is a distinctive trait of NFC and
brings several key advantages. First, due to the physical collocation of
transmitter/receiver, NFC does not require cumbersome network configuration and
can be used an out-of-band channels for secure device pairing without resorting
to a Public Key Infrastructure (PKI) or trusted third parties. Second, it
offers a natural, physical protection against various attacks, particularly
malicious eavesdropping. Due to these silent features, NFC is expected to
revolutionize a range of mobile applications, from contactless payment and
ticketing access control, to peripheral pairing smart devices. It is estimated
that the NFC market will grow to 34 billion by 2016.

However,
the widespread use of NFC is hindered by the fact that only a limited number of
smartphone/tablet platforms have built-in NFC chipsets. Moreover, in order to
support NFC on the existing industrial infrastructure like POS terminals, it
typically requires costly hardware and software upgrades, due to the need of
additional NFC chipsets and radio stack. As of 2012, it is estimated that only
3-5% and 12% the smartphones worldwide and in the U.S. have NFC support.
Moreover, while NFC does not incorporate any security at the physical or MAC
layers by assuming that the extremely short range of communication in itself
has offered a degree of physical protection, several recent findings have
brought the security of NFC into question. The eavesdropping distance of NFC is
empirically measured to be 30 cm. Our recent experimental study shows that,
with a specially designed portable NFC sniffer, it is possible to eavesdrop NFC
transmissions from up to 240 cm away, which is at least an order of magnitude
further than the intended NFC communication distance. These results have
seriously challenged the general perception that NFC is immune to
eavesdropping.Recently, NFC forum
proposed NFCIP-1 and NFC-SEC-01 specifications adopting utilize Diffie-Hellman key exchange protocol to enhance the data
confidentiality. However, most NFC applications are designed for
short-duration, rapid data exchange, and the lengthy key exchange process might
dominate the entire NFC communication session, compromising the user
experience.

This
project proposes alternative NFC
technologies that are secure and compatible with legacy devices (non-NFC
smartphones or even feature phones) and existing infrastructure (e.g., POS
terminals). The key novelty of our approach is to leverage visible light and acoustic channels to realize NFC systems with
robust performance and security assurance. First, we will design novel visible
light communication (VLC) techniques that can implement the functionality of
NFC. Due to the high directionality of narrow light beams, VLC can enable
secure and interference-free wireless links. In our approach, information can
be encoded as a stream of images and played on smartphone/computer screens
while the receiver uses camera to record and then decodes the video stream.
Second, we propose to modulate acoustic signal for NFC communication.
Leveraging the speaker and microphone, acoustic-based NFC systems can be purely
realized by software and offer compatibility with various smart devices without
additional hardware requirement.

Our approach offers several key
advantages over the existing NFC technology. First, both visual and acoustic
communication channels can be implemented using prevalent components such as
LCD displays, microphones, and speakers that are already available on
smartphones/tablets as well in retail stores, museums, etc.For instance, by leveraging the
abundance of LCD displays in retail stores, visual NFC can be implemented to
provide patrons with smartphones coupon brochures and maps. Therefore, our
approach will enable a purely
software-based solution that can easily retrofit existing infrastructure
with NFC functionality. Second, in contrast to RF technologies, the direction
and distance of screen-camera link can be easily controlled, preserving the
communication privacy and security. Similarly, integrated with physical layer
self-jamming techniques, the acoustic link can achieve information-theoretic
security without the need for any pre-shared secrets.

In this proposal, we propose to
design secure, robust and high-rate NFC systems for off-the-shelf devices such as
smartphones and POS terminals using visible light and acoustic channels. To
this end, we will address several key challenges, including limited compute
resources on smartphones, significant ambient light and acoustic noise, and the
susceptibility of eavesdropping of visual and acoustic communication channels.
Our approach optimizes the communication performance and achieves the security
assurance of visual and acoustic NFC by integrating novel technologies from
different domains, including acoustics-based communication, adaptive
self-jamming, automatic identification and data capture, barcode design,
lightweight image processing, and cryptography etc. Our research tasks are
outlined below:

Robust and
Dependable Barcode-based NFC.
The existing VLC approaches require complex signal processing techniques and
thus not suitable smartphones due to high computation overheads. To address
this challenge, we propose a new form of VLC to implement NFC, where 2D
barcodes are streamed between LCD display and camera. We propose a new 2D color
barcode design that is particularly optimized for real-time streaming between
small-size screens and low-speed cameras of smartphones. We propose several
novel techniques to optimize the throughput of screen-camera link between two
smartphones, which include code block adaptation and re-ordering to mitigate
the impact of image blur in mobile environments, and lightweight image
processing algorithms for real-time decoding of barcode stream. We further plan
to conduct a systematic security study of barcode-based communication system
and design physical layer security enhancement mechanisms. We will also
investigate full duplex, energy-efficient communication techniques for barcode
streaming NFC systems.

Dependable and
Secure Acoustics-based NFC.
We propose to investigate and design acoustics-based NFC system for
smartphones. The proposed design aims at providing a software-based solution to
secure smartphone communication without a priori knowledge of secrets. We
further propose to utilize the emerging friendly jamming technique from radio
communication for establishing an information-theoretically secure
communication channel. We also plan to explore advanced coding techniques,
high-level modulation schemes and other physical layer techniques for further
improving the data transmission rates and investigate other security-enhanced
techniques for providing stronger confidentiality guarantee.

System
Prototyping and Real-world Evaluation.
Prototyping and testing under real-world conditions are necessary and important
for evaluating the effectiveness of the proposed NFC systems. We will implement
the proposed designs on off-the-shelf smartphones and evaluate both the
performance and security of the communication performance. Specifically, for
both acoustic and light-based systems, we will implement on Android and iOS smartphone platforms and validate their performance
through extensive experiments under a range of settings on system parameters
and environmental factors, providing a complete performance characterization of
the software, hardware and environment on the off-the-shelf devices.